The Class Builder allows us to create and maintain global ABAP classes and interfaces. Both of these object types, like global data types, are defined in the ABAP Repository, thus composing a central class library. Together, they form a central class library and are visible throughout the system. We can display existing classes and interfaces in the class library using the Class Browser. We can define local classes as well as global classes. They are defined locally in programs, function groups or as auxiliary classes of global classes of the class pools. Local classes are only visible within the defining module. ABAP classes are processed using the Class Builder.